Personally I'm skeptical of their consultation. My vision is not terrible but just on my initial scan the lowercase vwxyz look too similar to their uppercase variants and I have difficulty with the lowercase l and 1. Without my glasses I wouldn't be able to tell those apart at all.
I have no idea about readability really; I have my preferences but I assume the experts know stuff I don’t, or at least know what works for a wide variety of people while I only know what works for me. The fact that IBM also validated their font with actual tests on people who need readability does lend some support to the consultants (assuming the focus group results and the consultant advice were in agreement).
the lowercase vwxyz look too similar to their uppercase variants
Is that likely to cause problems, do you think? You don’t generally need to read one of those characters on their own, they’ll be in context next to other characters. As long as you easily distinguish, say:
v0 V0
"v" "V"
If those are clear then I think it’ll be fine. And the relatively low x-height should help.
